In the drying section of a paper machine, apparatus for preventing conditions tending to deteriorate the contact between a web and a supporting fabric which carries the web from a drying cylinder in one line to a drying cylinder in another line and, in particular, for preventing a positive pressure from being generated in the narrowing gaps defined by the surfaces of the drying cylinders and the web supporting fabric as it approaches and/or moves away from the drying cylinder. The apparatus includes a blow box extending transversely substantially over the width of the web, the blow box including at least two transversely extending gas discharge slots between which a substantially planar carrying surface is provided in opposed, parallel relationship to the web carrying fabric and spaced a distance therefrom which is at least twice, and preferably ten to thirty times, as large as the width of a gas discharge slot.